Fix using indexes on sub Collections bug #36 (#37)

* Introduce end-of-line normalization

* bug fix using fields instead of properties

* fix bug #36

* make sure returns single record

* update to v2.3.3

src/Gridify.EntityFramework/Gridify.EntityFramework.csproj

@@ -9,7 +9,7 @@
    <PropertyGroup>
       <TargetFramework>netstandard2.0</TargetFramework>
       <PackageId>Gridify.EntityFramework</PackageId>
-      <Version>2.3.2</Version>
+      <Version>2.3.3</Version>
       <Authors>Alireza Sabouri</Authors>
       <Company>TuxTeam</Company>
       <PackageDescription>Gridify (EntityFramework), Easy and optimized way to apply Filtering, Sorting, and Pagination using text-based data.</PackageDescription>

src/Gridify/Gridify.csproj

@@ -3,7 +3,7 @@
    <PropertyGroup>
       <TargetFramework>netstandard2.0</TargetFramework>
       <PackageId>Gridify</PackageId>
-      <Version>2.3.2</Version>
+      <Version>2.3.3</Version>
       <Authors>Alireza Sabouri</Authors>
       <Company>TuxTeam</Company>
       <PackageDescription>Gridify, Easy and optimized way to apply Filtering, Sorting, and Pagination using text-based data.</PackageDescription>

src/Gridify/Syntax/SyntaxTreeToQueryConvertor.cs

@@ -43,11 +43,8 @@ private static (Expression<Func<T, bool>> Expression, bool IsNested)? ConvertBin
 
       private static LambdaExpression UpdateExpressionIndex(LambdaExpression exp, int index)
       {
-         var parameter = exp.Parameters[0];
-         var unary = exp.Body as UnaryExpression;
-         var body = unary!.Operand as MemberExpression;
-         var newBody = new PredicateBuilder.ReplaceExpressionVisitor(exp.Parameters[1], Expression.Constant(index, typeof(int))).Visit(body!);
-         return Expression.Lambda(newBody, parameter);
+         var body = new PredicateBuilder.ReplaceExpressionVisitor(exp.Parameters[1], Expression.Constant(index, typeof(int))).Visit(exp.Body);
+         return Expression.Lambda(body, exp.Parameters);
       }
 
       private static Expression<Func<T, bool>>? GenerateNestedExpression<T>(
@@ -107,7 +104,7 @@ private static ParameterExpression GetParameterExpression(MemberExpression membe
       private static LambdaExpression GetAnyExpression(MemberExpression member, Expression predicate)
       {
          var param = GetParameterExpression(member);
-         var prop = Expression.Property(param!, member.Member.Name);
+         var prop = Expression.PropertyOrField(param!, member.Member.Name);
 
          var tp = prop.Type.GenericTypeArguments[0];
          var anyMethod = GetAnyMethod(tp);

test/Gridify.Tests/Issue36Tests.cs

@@ -0,0 +1,86 @@
+using System.Collections.Generic;
+using System.Linq;
+using Xunit;
+
+namespace Gridify.Tests
+{
+   // issue #36 - https://github.com/alirezanet/Gridify/issues/36
+   public class Issue36Tests
+   {
+      [Fact]
+      private void UserReportTest1()
+      {
+         List<Level1> level1List = new List<Level1>();
+         level1List.Add(new Level1());
+
+         var gridifyMapper = new GridifyMapper<Level1>().GenerateMappings()
+            .AddMap("level4_property1", (l1, index) => l1.Level2List.Select(x => x.Level3.Level4List[index].Property1));
+
+         var gridifyQuery = new GridifyQuery() { Filter = "level4_property1[0] > 5" };
+         var query = gridifyQuery.GetFilteringExpression(gridifyMapper);
+         var expression = query.Compile();
+
+         var actual = level1List.Where(expression).ToList();
+
+         Assert.Single(actual);
+         Assert.True(actual.Any());
+      }
+
+      public class Level1
+      {
+         public string Name { get; set; }
+
+         public List<Level2> Level2List = new List<Level2>()
+         {
+            new Level2()
+            {
+               Name = "1",
+               Level3 = new Level3()
+               {
+                  Name = "2",
+                  Level4List = new List<Level4>()
+                  {
+                     new Level4() { Name = "3", Property1 = 3, Property2 = 4 },
+                     new Level4() { Name = "4", Property1 = 4, Property2 = 5 },
+                     new Level4() { Name = "5", Property1 = 5, Property2 = 6 }
+                  }
+               }
+            },
+
+            new Level2()
+            {
+               Name = "6",
+               Level3 = new Level3()
+               {
+                  Name = "7",
+                  Level4List = new List<Level4>()
+                  {
+                     new Level4() { Name = "8", Property1 = 8, Property2 = 9 },
+                     new Level4() { Name = "9", Property1 = 9, Property2 = 10 },
+                     new Level4() { Name = "10", Property1 = 10, Property2 = 11 }
+                  }
+               }
+            },
+         };
+      }
+
+      public class Level2
+      {
+         public string Name { get; set; }
+         public Level3 Level3 = new Level3();
+      }
+
+      public class Level3
+      {
+         public string Name { get; set; }
+         public List<Level4> Level4List = new List<Level4>();
+      }
+
+      public class Level4
+      {
+         public string Name { get; set; }
+         public double Property1 { get; set; }
+         public double Property2 { get; set; }
+      }
+   }
+}